"So instead of 30 out of the thousand dying from prostate cancer by age 85, only 28 will die of prostate cancer. By the time they are 85, about 640 will have died from all causes of death whether they were screened or not," she said. "Higher risk men have more prostate cancer deaths averted, but also more prostate cancer diagnosed and related harms."
From the model, screened men are about two to four times more likely to be diagnosed with prostate cancer than men who do not get the screening, but death rates from prostate cancer and from other causes are similar in both groups, Howard said.
"The net mortality benefit is small, and this needs to be weighed against the increased chances of being diagnosed and treated for prostate cancer," she said. "Before undergoing PSA screening, men should be aware of the possible benefits and harms, and of their chances of these benefits and harms occurring."
Dr. Michael Pignone, an assistant professor of cancer prevention and control at the University of North Carolina at Chapel Hill and author of an accompanying journal editorial, said that "when you total up the potentially beneficial and potential detrimental consequences of PSA screening, it is not clear that the net effect of PSA screening is beneficial."
Pignone noted that the consequences of prostate cancer treatment, such as impotence and incontinence, occur with treatment. "You suffer the down sides right away," he said. "You only get the benefits, in most cases, far into the future."
Pignone noted that even men with prostate cancer are more likely to die from heart disease or dementia than their cancer. Your chance of dying from prostate cancer is one in a 1,000, while the odds of dying from another cause is 113 in 1,000, he said.
Brawley noted that the American Cancer Society is reviewing its recommendations for PSA screening, and is expected to change them next year.
"Men should know that there are huge question marks, and for some men who are very concerned, perhaps they should get screened. For some men who are less concerned about prostate cancer, perhaps they should not get screened," Brawley said. "But men should not be told that prostate cancer screening is more beneficial than we have evidence to show."
For more information on prostate cancer, visit the American Cancer Society.
SOURCES: Richard M. Hoffman, M.D., M.P.H., New Mexico VA Health Care System, associate professor of medicine, University of New Mexico School of Medicine, Albuquerque; Kirsten Howard, Ph.D., senior lecturer, health economics, University of Sydney, Australia; Michael Pignone, M.D., M.P.H., assistant professor, cancer prevention and control, University of North Carolina, Chapel Hill; Otis W. Brawley, M.D., chief medical officer, American Cancer Society; Sept. 28, 2009, Archives of Internal Medicine